Information transmission apparatus and system using inductive coupling between coils

ABSTRACT

An information transmission system is provided with a transmission coil and a reception coil respectively provided along a first surface and a second surface that face each other proximal to each other. The transmission coil and reception coil are provided proximally to be electromagnetically coupled to each other. The winding wire of the transmission coil is wound on the first surface, and the winding wire of the reception coil is wound on the second surface. The information transmission system is provided with a magnetic body provided proximately so as to be electromagnetically coupled to the transmission coil and the reception coil to cover at least one part of a region in which at least the winding wires of the transmission coil and reception coil are present between the first surface and the second surface.

TECHNICAL FIELD

The present disclosure relates to a noncontact connector apparatus and anoncontact connector system, each using inductive coupling betweencoils, and an information transmission apparatus and an informationtransmission system including the same apparatus and system.

BACKGROUND ART

In recent years, to perform wireless charging in an electronic deviceand an EV device with mobility such as portable telephones and electricvehicles, developments of a noncontact connector apparatus and anoncontact connector system using inductive coupling between coils, anda power transfer apparatus and a power transfer system including thesame apparatus and system have been promoted. As a noncontact powertransfer system, for example, the inventions of the Patent Documents 1to 3 have been known.

The noncontact power feeding apparatus of the Patent Document 1 ischaracterized by including a furniture with a power primary coilsupplied with electric power, a cordless device including a powersecondary coil arranged in magnetic fluxes caused by the power primarycoil in such a state that the same apparatus is arranged in apredetermined arrangement position with respect to the furniture, andinforming means for informing of the predetermined arrangement positionof the cordless device with respect to the furniture.

The contactless power transfer coil of the Patent Document 2 ischaracterized by including a planar coil formed by winding a linearconductor in a spiral form within a roughly identical plane, and amagnetic layer that is formed by coating a liquid magnetic materialsolution in which magnetic particles are mixed in a binder solvent andcoated so as to cover one planar portion of the planar coil and a sidesurface portion of the planar coil.

The wireless transmission system of the Patent Document 3 includes aresonator for wireless power transfer, and this has a conductor thatforms one or more loops and has a predetermined inductance, and acapacitor network that has predetermined capacitances and desiredelectrical parameters and is connected to the conductor. In this case,the capacitor network includes at least one capacitor of a first typehaving a first temperature profile as an electrical parameter, and atleast one capacitor of a second type having a second temperature profileas an electrical parameter.

The principle of such a noncontact power transfer system is applicablealso to an information transmission system including a noncontactconnector apparatus and an induction heating apparatus such as an IHcooking apparatus and the like.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese patent laid-open publication No. JP    2001-309579 A;-   Patent Document 2: Japanese patent laid-open publication No. JP    2008-172873 A; and-   Patent Document 3: U.S. patent application publication No. US    2010/0181845 A1.

SUMMARY OF THE INVENTION Problems to be Dissolved

In order to achieve a high transmission efficiency in a noncontact powertransfer system, it is beneficial to make a transmitter coil providedfor the power transfer apparatus (e.g., charger) on the transmitter sideand a receiver coil provided for the power transfer apparatus (e.g.,object to be charged) on the receiver side opposed to each otheraccurately aligned in position so that the transmitter coil and thereceiver coil are electromagnetically strongly coupled to each other.

According to the inventions of the Patent Documents 1 and 2, there issuch a problem that the transmission efficiency decreases when apositional misalignment occurs despite that a high transmissionefficiency can be achieved when the opposed transmitter coil andreceiver coil opposed to each other are accurately aligned in position.

In order to solve the decrease in the transmission efficiency due topositional misalignment, an impedance matching circuit is dynamicallychanged in the invention of the Patent Document 3. However, such asolution method had such a problem that the controlling becomescomplicated.

Similar problems exist in not only noncontact power transfer systems butalso information transmission systems with noncontact connectors andinduction heating apparatuses.

An object of the present disclosure is to provide an informationtransmission apparatus and an information transmission system that aretolerant of positional misalignment of the transmitter coil and thereceiver coil and has a high transmission efficiency with a simpleconfiguration.

Means for Dissolving the Problems

According to a first aspect of the present disclosure, there is providedan information transmission apparatus including a transmitter circuitconfigured to transmit information to a receiver circuit connected to areceiver coil; and a first noncontact connector apparatus connected tothe transmitter circuit. The first noncontact connector apparatuscomprises a transmitter coil, that is provided to be adjacent so as tobe electromagnetically coupled to the receiver coil, and a winding ofthe transmitter coil is wound on a first plane. The informationtransmission apparatus includes a first magnetic body provided betweenthe first plane and a second plane which is opposed to be adjacent tothe first plane and on which the receiver coil is provided, and thefirst magnetic body is provided to be adjacent so as to beelectromagnetically coupled to the transmitter coil and to cover atleast one part of a region in which at least the winding of thetransmitter coil exists.

According to a second aspect of the present disclosure, there isprovided an information transmission apparatus including: a receivercircuit configured to receive information from a transmitter circuitconnected to a transmitter coil; and a second noncontact connectorapparatus connected to the receiver circuit. The second noncontactconnector apparatus includes a receiver coil, that is provided to beadjacent so as to be electromagnetically coupled to the transmittercoil, and a winding of the receiver coil is wound on a second plane thatis opposed to be adjacent to the first plane on which the transmittercoil is provided. The information transmission apparatus includes asecond magnetic body provided between the first plane and the secondplane, and the second magnetic body is provided to be adjacent so as tobe electromagnetically coupled to the receiver coil and to cover atleast one part of a region in which at least the winding of the receivercoil exists.

According to a third aspect of the present disclosure, there is providedan information transmission system including: the informationtransmission apparatus according to the first or second aspect of thepresent disclosure serving as a first information transmission apparatusincluding the transmitter circuit; and a second information transmissionapparatus including the receiver circuit, and a second noncontactconnector apparatus connected to the receiver circuit. The secondnoncontact connector apparatus comprises a receiver coil including awinding wound on the second plane. The first magnetic body is furtherput to be adjacent to the receiver coil to be electromagneticallycoupled to the receiver coil and to cover at least one part of a regionin which at least the winding of the receiver coil exists between thefirst plane and the second plane, thereby increasing the self-inductanceof the receiver coil by putting the first magnetic body to be adjacentto the receiver coil. A coupling coefficient between the transmittercoil and the receiver coil is set to be decreased by increasing theself-inductance of each of the transmitter coil and the receiver coil sothat a frequency characteristic of transmission efficiency from thetransmitter coil to the receiver coil changes from a double-peakednarrow-band characteristic to a single-peaked wide-band characteristic.

According to a fourth aspect of the present disclosure, there isprovided an information transmission system including: the informationtransmission apparatus according the first or second aspect of thepresent disclosure serving as a first information transmission apparatusincluding the transmitter circuit; and the information transmissionapparatus according to the third or fourth aspect of the presentdisclosure serving as a second information transmission apparatusincluding the receiver circuit. A coupling coefficient between thetransmitter coil and the receiver coil is set to be decreased byincreasing the self-inductance of each of the transmitter coil and thereceiver coil so that a frequency characteristic of transmissionefficiency from the transmitter coil to the receiver coil changes from adouble-peaked narrow-band characteristic to a single-peaked wide-bandcharacteristic.

Effect of the Invention

According to the information transmission apparatus and the informationtransmission system of the present disclosure, information can betransmitted with a stabilized transmission efficiency with a very simpleconfiguration even if positional misalignment occurs between thetransmitter coil and the receiver coil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a schematic configuration of apower transfer system according to a first embodiment of the presentdisclosure;

FIG. 2 is a sectional view along a line A-A′ of FIG. 1;

FIG. 3 is a sectional view showing a schematic configuration of a powertransfer system of a comparative example;

FIG. 4 is a circuit diagram showing one example of an equivalent circuitof the power transfer system of FIG. 3;

FIG. 5 is a schematic diagram showing frequency characteristics oftransmission efficiency when a coupling coefficient k between atransmitter coil 1 and a receiver coil 2 of FIG. 3 is changed;

FIG. 6 is a schematic diagram showing flows of magnetic fluxes in thepower transfer system of FIG. 3;

FIG. 7 is a schematic diagram showing flows of magnetic fluxes when adistance d between the transmitter coil 1 and the receiver coil 2 isincreased in the power transfer system of FIG. 3;

FIG. 8 is a schematic diagram showing flows of magnetic fluxes when thedistance “d” between the transmitter coil 1 and the receiver coil 2 isincreased and a magnetic material 6 is inserted in the power transfersystem of FIG. 3;

FIG. 9 is a schematic diagram showing flows of magnetic fluxes in thepower transfer system of FIG. 1;

FIG. 10 is a schematic diagram showing flows of magnetic fluxes when thetransmitter coil 1 and the receiver coil 2 are misaligned in position inthe power transfer system of FIG. 1;

FIG. 11 is a perspective view showing a schematic configuration of apower transfer system according to a first implemental example of thepresent disclosure;

FIG. 12 is a top view of the power transfer system of FIG. 11;

FIG. 13 is a sectional view along a line B-B′ of FIG. 11;

FIG. 14 is a circuit diagram showing an equivalent circuit of the powertransfer system of FIG. 11;

FIG. 15 is a diagram showing a positional misalignment generated betweenthe transmitter coil 1 and the receiver coil 2 in the power transfersystem of FIG. 11;

FIG. 16 is a graph showing frequency characteristics of transmissionefficiency when the positional misalignment of the transmitter coil 1and the receiver coil 2 is changed in the power transfer system of FIG.11 from which the magnetic material 3 is removed;

FIG. 17 is a graph showing frequency characteristics of transmissionefficiency when the positional misalignment of the transmitter coil 1and the receiver coil 2 is changed in the power transfer system of FIG.11;

FIG. 18 is a graph showing characteristics of transmission efficiencywith respect to the positional misalignment of the power transfer systemof FIG. 11;

FIG. 19 is a graph showing frequency characteristics of transmissionefficiency when a relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 11;

FIG. 20 is a graph showing frequency characteristics of transmissionefficiency when the relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 11 in which the thicknessof the magnetic material 3 is reduced;

FIG. 21 is a graph showing frequency characteristics of transmissionefficiency when the relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 11 in which the thicknessof the magnetic material 3 is reduced;

FIG. 22 is a top view showing a schematic configuration of a powertransfer system according to a second implemental example of the presentdisclosure;

FIG. 23 is a graph showing frequency characteristics of transmissionefficiency when the relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 22 from which a cavity isremoved;

FIG. 24 is a graph showing frequency characteristics of transmissionefficiency when the relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 22;

FIG. 25 is a sectional view showing a schematic configuration of a powertransfer system according to a third implemental example of the presentdisclosure;

FIG. 26 is a plan view showing a transmitter coil 1 and a receiver coil2 of FIG. 25;

FIG. 27 is a graph showing frequency characteristics of transmissionefficiency of the power transfer system of FIG. 25;

FIG. 28 is a block diagram showing a schematic configuration of thepower transfer system of the first embodiment of the present disclosure;

FIG. 29 is a sectional view showing a configuration of a power transferapparatus on the power transmitter side and a power transfer apparatuson the power receiver side in the power transfer system of FIG. 25;

FIG. 30 is a sectional view showing a configuration of a modifiedembodiment of the power transfer apparatus on the power transmitter sideand the power transfer apparatus on the power receiver side in the powertransfer system of FIG. 25;

FIG. 31 is a block diagram showing a schematic configuration of a signaltransmission system according to a second embodiment of the presentdisclosure;

FIG. 32 is a block diagram showing a schematic configuration of aninduction heating apparatus according to a third embodiment of thepresent disclosure;

FIG. 33 is a sectional view showing a configuration of the inductionheating apparatus and the pan 123 of FIG. 32;

FIG. 34 is a sectional view showing a modified embodiment of thetransmitter coil 1 and the receiver coil 2 of FIG. 1;

FIG. 35 is a schematic diagram for explaining a winding method of thetransmitter coil 1 of FIG. 34;

FIG. 36 is a schematic diagram for explaining a modified embodiment ofthe winding method of the transmitter coil 1 of FIG. 34;

FIG. 37 is a sectional view showing a modified embodiment of thenoncontact connector apparatuses on the transmitter side and the powerreceiver side of FIG. 1;

FIG. 38 is a perspective view showing a schematic configuration of apower transfer system according to a fourth embodiment of the presentdisclosure;

FIG. 39 is a perspective view showing a schematic configuration of apower transfer system according to a fifth embodiment of the presentdisclosure;

FIG. 40 is a vertical sectional view showing a schematic configurationof a power transfer system according to a fourth implemental example ofthe present disclosure; and

FIG. 41 is a graph showing characteristics of the coupling coefficient kwith respect to a permeability ratio μ2/μ1 when a normalized inter-coildistance d/D is used as a parameter in the power transfer system of FIG.40.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described below withreference to the drawings. It is noted that like components are denotedby like reference numerals.

First Embodiment

FIG. 1 is a perspective view showing a schematic configuration of apower transfer system according to the first embodiment of the presentdisclosure. FIG. 2 is a sectional view along a line A-A′ of FIG. 1. Thepower transfer system of the present embodiment is configured to includea noncontact connector system that uses electromagnetical couplingbetween a transmitter coil 1 and a receiver coil 2. In FIG. 1 and otherfigures, a power supply, a power transmitter circuit, a power receivercircuit and so on which is beneficial for use in a power transfer systemare omitted for simplicity of illustration, and only the noncontactconnector system is shown. It is noted that the noncontact connectorsystem is assumed to be configured to include a noncontact connectorapparatus that includes a transmitter coil 1 on the transmitter side,and a noncontact connector apparatus that includes a receiver coil 2 onthe receiver side.

In the power transfer system of FIG. 1, the noncontact connector systemis configured to include the transmitter coil 1 and the receiver coil 2,which are provided along a first plane and a second plane, respectively,and arranged to be adjacent and oppose to each other. The transmittercoil 1 has terminals P1 a and P1 b, and the receiver coil 2 hasterminals P2 a and P2 b. The transmitter coil 1 and the receiver coil 2are arranged to be adjacent to each other so as to beelectromagnetically coupled to each other. The transmitter coil 1 isprovided along the first plane so that its winding is wound around theperipheries of a predetermined region on the first plane. Likewise, thereceiver coil 2 is provided along the second plane so that its windingis wound around the peripheries of a predetermined region on the secondplane. The noncontact connector system is configured to include amagnetic material 3 having a predetermined relative permeability. Themagnetic material 3 is provided between the first and second planes, soas to be electromagnetically coupled to the transmitter coil 1 and thereceiver coil 2 and to cover at least one part of a region, in which thewindings of the transmitter coil 1 and the receiver coil 2 exist betweenthe first plane and the second plane. The magnetic material 3 is madeof, for example, ferrite. A self-inductance of the transmitter coil 1 isincreased by putting the magnetic material 3 to be adjacent to themagnetic material 3, and a self-inductance of the receiver coil 2 isincreased by putting the magnetic material 3 to be adjacent to thereceiver coil 2.

The power transfer system of the present embodiment is characterized inthat a coupling coefficient between the transmitter coil 1 and thereceiver coil 2 is set to be decreased by increasing theself-inductances of the transmitter coil 1 and the receiver coil 2, sothat a frequency characteristic of transmission efficiency from thetransmitter coil 1 to the receiver coil 2 changes from a double-peakednarrow-band characteristic to a single-peaked wide-band characteristic.

The principle of operation of the noncontact connector system of thepresent embodiment will be described below.

FIG. 3 is a sectional view showing a schematic configuration of thepower transfer system of a comparative example. In the power transfersystem of FIG. 3, the noncontact connector system is similar to thenoncontact connector system of FIG. 1 except for not having the magneticmaterial 3. The transmitter coil 1 is provided in a casing 4 of thenoncontact connector apparatus on the transmitter side, and the receivercoil 2 is provided in a casing 5 of the noncontact connector apparatuson the receiver side. The transmitter coil 1 and the receiver coil 2 areseparated to be apart by a distance d provided therebetween.

In the power transfer system of FIG. 3, when a current flows in thetransmitter coil 1, an induced electromotive force is generated at thereceiver coil 2 due to electromagnetic fields in the peripheries of thetransmitter coil 1 formed by the current, and an induced current flowsin the receiver coil 2. In other words, the transmitter coil 1 and thereceiver coil 2 are electromagnetically coupled to each other. Thecoupling coefficient k of the following equation is used as an index toevaluate the degree of the coupling:

${k = {{\frac{M}{\sqrt{L\; 1} \times \sqrt{L\; 2}}\mspace{14mu} {for}\mspace{14mu} 0} \leq {k} \leq 1}},$

where M represents an mutual inductance between the transmitter coil 1and the receiver coil 2, L1 represents the self-inductance of thetransmitter coil 1, and L2 represents the self-inductance of thereceiver coil 2.

FIG. 4 is a circuit diagram showing one example of an equivalent circuitof the power transfer system of FIG. 3. Q is a signal source, z01 is theload impedance of the transmitter circuit, and z02 is the load impedanceof the receiver circuit and the load. R1 and R2 are resistors, and C1and C2 are capacitors for impedance matching. When the power transfersystem operates at an angular frequency ω, a parameter S21 representinga transmission efficiency can be expressed by the following equationusing the self-inductances L1 and L2, and the mutual inductance M:

                                     [Equation  1]${S\; 21} = \frac{j \cdot 2 \cdot \omega \cdot M \cdot \sqrt{{{Re}\left\lbrack {z\; 01} \right\rbrack} \cdot {{Re}\left\lbrack {z\; 02} \right\rbrack}}}{{\begin{pmatrix}{\left( {{R\; 1} + {z\; 01}} \right) + {j \cdot}} \\\left( {{{\omega \cdot L}\; 1} - \frac{1}{{\omega \cdot C}\; 1}} \right)\end{pmatrix} \cdot \begin{pmatrix}{\left( {{R\; 2} + {z\; 02}} \right) + {j \cdot}} \\\left( {{{\omega \cdot L}\; 2} - \frac{1}{{\omega \cdot C}\; 2}} \right)\end{pmatrix}} + \left( {\omega \cdot M} \right)^{2}}$

It is noted that the equivalent circuit of FIG. 4 and the expression ofthe parameter S21 are mere examples, and the equivalent circuit and thetransmission efficiency of the power transfer system may be expressed byother arbitrary appropriate models.

When the transmitter coil 1 and the receiver coil 2 areelectromagnetically strongly coupled to each other, |k|≈1. However, thevalue of |k| decreases as the distance d increases, and |k|=0 when thetransmitter coil 1 and the receiver coil 2 are not electromagneticallycoupled to each other.

FIG. 5 is a schematic graph showing frequency characteristics oftransmission efficiency when the coupling coefficient k between thetransmitter coil 1 and the receiver coil 2 of FIG. 3 is changed. In FIG.5, it is assumed that the Q value is constant. According to FIG. 5, itcan be understood that the bandwidth of transmission efficiency changesin accordance with the magnitude of the coupling coefficient k.Normally, when the electromagnetic coupling of the transmitter coil 1and the receiver coil 2 is strong, a double-peaked narrow-bandcharacteristic results, and wide band operation cannot be achieved. Thatis, in order to achieve wide band operation, it is beneficial to lowerthe coupling coefficient k under the condition that the transmitter coil1 and the receiver coil 2 are adjacent to each other. Since the couplingcoefficient k is a ratio of the square root of the self-inductances L1and L2 to the mutual inductance M, the coupling coefficient k can bedecreased if the self-inductances L1 and L2 can be increased.

FIGS. 6 to 8 are schematic diagrams showing flows of magnetic fluxes inthe power transfer system of FIG. 3, respectively. In FIGS. 6 to 8, thecasings 4 and 5 of FIG. 3 are omitted, and the transmitter coil 1 andthe receiver coil 2 are only shown. In a case where the transmitter coil1 and the receiver coil 2 are adjacent to each other as shown in FIG. 6,when a current flows in the transmitter coil 1, magnetic fluxes M1 a andM1 b are formed so as to surround both of the transmitter coil 1 and thereceiver coil 2, and the mutual inductance M increases, making thecoupling coefficient k higher. FIG. 7 is a schematic diagram showingflows of magnetic fluxes when the distance d between the transmittercoil 1 and the receiver coil 2 is increased in the power transfer systemof FIG. 3. In a case where the transmitter coil 1 and the receiver coil2 are apart from each other as shown in FIG. 7, when a current flows inthe transmitter coil 1, magnetic fluxes M2 a and M2 b partially becomeleakage fluxes among the magnetic fluxes formed in the peripheries ofthe transmitter coil 1 and receiver coil 2, and therefore, the mutualinductance M decreases, making the coupling coefficient k lower. FIG. 8is a schematic diagram showing flows of the magnetic fluxes when thedistance d between the transmitter coil 1 and the receiver coil 2 isincreased, and a magnetic material 6 is inserted in the power transfersystem of FIG. 3. In a case where the transmitter coil 1 and thereceiver coil 2 are apart from each other, by inserting the magneticmaterial 6 (iron, ferrite, or the like) in the center portion of thetransmitter coil 1 and the receiver coil 2 as shown in FIG. 8, theleakage fluxes M2 a and M2 b of FIG. 7 can be changed into a magneticflux M1 b surrounding both of the transmitter coil 1 and the receivercoil 2 through the inside of the magnetic material 6, consequentlyincreasing the mutual inductance M and making the coupling coefficient khigher.

Under the condition that the transmitter coil 1 and the receiver coil 2are adjacent to each other as shown in FIG. 6, the coupling coefficientk becomes higher as described before, and therefore, any wide bandoperation cannot be achieved. Therefore, it is beneficial to increasethe self-inductances L1 and L2 by controlling the flows of the magneticfluxes instead of decreasing the mutual inductance M.

FIG. 9 is a schematic diagram showing flows of magnetic fluxes in thepower transfer system of FIG. 1. When a current flows in the transmittercoil 1, a partial magnetic flux M1 is formed so as to surround both ofthe transmitter coil 1 and the receiver coil 2 through the magneticmaterial 3. However, the other partial magnetic flux M2 a is notdirected toward the receiver coil 2 passing only in the vicinity of thetransmitter coil 1 in the magnetic material 3 and but formed as aleakage flux surrounding only the transmitter coil 1. By forming theleakage flux M2 a, the self-inductance L1 of the transmitter coil 1increases. Likewise, when an induced current flows in the receiver coil2, the magnetic flux is not directed toward the transmitter coil 1passing only in the vicinity of the receiver coil 2 in the magneticmaterial 3, but forms the leakage flux M2 b surrounding only thereceiver coil 2. By forming the leakage flux M2 b, the self-inductanceL2 of the receiver coil 2 increases. As described above, in the powertransfer system of FIG. 1, the self-inductances L1 and L2 increase dueto the magnetic material 3 provided, and the coupling coefficient k isdecreased by comparison with the case of FIG. 6, therefore allowing thewide band operation to be achieved.

FIG. 10 is a schematic diagram showing flows of magnetic fluxes when thetransmitter coil 1 and the receiver coil 2 are misaligned in position inthe power transfer system of FIG. 1. In this case also, the leakage fluxM2 a surrounding only the transmitter coil 1 and the leakage flux M2 bsurrounding only the receiver coil 2 are formed in a manner similar tothat of the case of FIG. 9. Therefore, the self-inductances L1 and L2increase due to the magnetic material 3 provided in a manner similar tothat of the case of FIG. 9, and the coupling coefficient k is decreasedby comparison with the case of FIG. 6, and therefore this allows thewide band operation to be achieved.

The beneficial coupling coefficient k is described with reference toFIG. 5. As described above, when the electromagnetic coupling of thetransmitter coil 1 and the receiver coil 2 is strong, the double-peakednarrow-band characteristic results. However, when the couplingcoefficient k gradually decreases, a frequency interval between the twopeaks of transmission efficiency gradually decreases, and the minimumvalue of transmission efficiency between the two peaks graduallyincreases. When the frequency interval becomes substantially zero, i.e.,when a difference between the two peaks of transmission efficiency andthe minimum value between them decreases (e.g., 5 to 10%), the bandwidthof the power transfer system is maximized. The coupling coefficient k isdetermined so as to satisfy this beneficial point, and the parameters(the thickness and the relative permeability of the magnetic material 3,the number of turns of the transmitter coil 1 and the receiver coil 2,etc.) of the power transfer system are determined so as to achieve thisvalue of the coupling coefficient k.

When the magnetic material 3 is provided between the transmitter coil 1and the receiver coil 2 that are separated to be apart by the distance dprovided therebetween, a single-peaked wide-band characteristic resultsin the presence of the magnetic material (“d=2.6 mm with the magneticmaterial”, a plot of solid line) in contrast to the double-peakednarrow-band characteristic in the absence of the magnetic material(“d=2.6 mm with no magnetic material”, a plot of alternate long andshort line) as described later with reference to FIG. 27. Although thedouble-peaked characteristic is exhibited in the case of the powertransfer system in the absence of the magnetic material since thecoupling coefficient k is high, the coupling coefficient k decreases dueto the effects of the magnetic material 3, and wide band operation canbe achieved in the case of the power transfer system of the presentembodiment. Moreover, according to FIG. 27, when the case in the absenceof the magnetic material (“d=2.6 mm with no magnetic material”, a plotof alternate long and short dash line) and the case in the presence ofthe magnetic material (“d=2.6 mm with the magnetic material”, a plot ofsolid line) are compared with each other, the resonance frequencydecreases from 250 kHz to 150 kHz due to increases in theself-inductances L1 and L2 when the magnetic material 3 is provided. Inother words, a size reduction effect can also be obtained due to thedecrease in the resonance frequency in the power transfer system of thepresent embodiment.

Next, the tolerance of the power transfer system of the presentembodiment with regard to the positional misalignment of the transmittercoil 1 and the receiver coil 2 is described with reference to FIGS. 11to 18.

FIG. 11 is a perspective view showing a schematic configuration of thepower transfer system according to the first implemental example of thepresent disclosure. FIG. 12 is a top view of the power transfer systemof FIG. 11. FIG. 13 is a sectional view along a line B-B′ of FIG. 11.The transmitter coil 1 and the receiver coil 2 are rectangular coilsthat have square outer peripheries of 30 mm×30 mm, a wiring width of 0.4mm, a wiring pitch of 0.4 mm, and a wiring thickness of 0.2 mm, and anumber of turns is five. The transmitter coil 1 and the receiver coil 2are opposed to each other at a distance d=2 mm provided therebetween. Aferrite magnetic material 3 having a thickness of 2 mm and a relativepermeability of 10 is provided between the transmitter coil 1 and thereceiver coil 2. FIG. 14 is a circuit diagram showing an equivalentcircuit of the power transfer system of FIG. 11. Q1 is a signal source,Z1 is a load impedance, and C3 and C4 are capacitors loaded forimpedance matching. The capacitors C3 and C4 have a capacitance of 20nF. FIG. 15 is a diagram for explaining positional misalignmentsgenerated between the transmitter coil 1 and the receiver coil 2 in thepower transfer system of FIG. 11. The receiver coil 2 was displaced inthe Y direction with respect to the transmitter coil 1 as shown in FIG.15. It is assumed that the magnetic material 3 has a sufficient lengthin the Y direction so that the displacement in FIG. 15 can be achieved.

According to computer simulations (FIGS. 16 to 21, FIG. 23 and FIG. 24),an impedance matrix between the transmitter coil 1 and the receiver coil2 was calculated by using the finite element method, and 100×|S21|² wasobtained as a transmission efficiency between the transmitter coil 1 andthe receiver coil 2.

FIG. 16 is a graph showing a frequency characteristic of transmissionefficiency when the positional misalignment of the transmitter coil 1and the receiver coil 2 is changed in the power transfer system of FIG.11 from which the magnetic material 3 is removed. FIG. 17 is a graphshowing a frequency characteristic of transmission efficiency when thepositional misalignment of the transmitter coil 1 and the receiver coil2 is changed in the power transfer system of FIG. 11. It can beunderstood that the resonance frequency shifts to a higher frequency asthe displacement between the transmitter coil 1 and the receiver coil 2increases, and the transmission efficiency decreases in the absence ofthe magnetic material 3 (FIG. 16). Assuming that the operating frequencyis about 700 kHz, then large fluctuations occur in the transmissionefficiency. This is because the magnetic fluxes that penetrate betweenthe transmitter coil 1 and the receiver coil 2 decrease, and the mutualinductance M decreases as a consequence of a displacement in positionbetween the transmitter coil 1 and the receiver coil 2. On the otherhand, it can be understood that the fluctuations in the transmissionefficiency are suppressed low by the effect of increasing the bandwidthin the power transfer system that includes the magnetic material 3 (FIG.17) of the present embodiment. That is, it can be understood that thepower transfer system of the present embodiment has such a particularadvantageous effect as having a great tolerance to the positionalmisalignment.

FIG. 18 is a graph showing a characteristic of transmission efficiencywith respect to the positional misalignment of the power transfer systemof FIG. 11. The configuration of the power transfer system is similar tothat shown in FIGS. 11 to 14, and the operating frequency is 680 kHz.For example, when a range in which the transmission efficiency becomesequal to or larger than 60% is obtained, the comparative example (withno magnetic material) is tolerant of a displacement of up to 5 mm, andthe implemental example is tolerant of a positional misalignment up to13 mm. It can be understood that the power transfer system of thepresent embodiment has a great tolerance to the positional misalignmentof the transmitter coil 1 and the receiver coil 2.

The fact that the tolerance to the positional misalignment is increasedmeans that the relative change of the coupling coefficient is small evenif the transmitter coil 1 and the receiver coil 2 are misaligned inposition.

Next, a characteristic when the relative permeability of the magneticmaterial 3 is changed in the power transfer system of the presentembodiment is described with reference to FIGS. 19 to 21. In FIGS. 19 to21, the configuration of the power transfer system is similar to thatshown in FIGS. 11 to 14 except for the thickness (equal to the distancebetween the transmitter coil 1 and the receiver coil 2) and the relativepermeability of the magnetic material 3. It is noted that the capacitorsC3 and C4 have a capacitance of 10 nF.

FIG. 19 is a graph showing a frequency characteristic of transmissionefficiency when the relative permeability of the magnetic material 3 ischanged in the power transfer system of FIG. 11. In the case of FIG. 19,the thickness of the magnetic material 3 is 2 mm. According to FIG. 19,a double-peaked characteristic is exhibited when the relativepermeability μ_(r)=2, whereas a wide-band characteristic is exhibitedwith the transmission efficiency maintained when the relativepermeability μ_(r)=7, and a single-peaked characteristic is exhibitedwhen the relative permeability μ_(r)=20 with the transmission efficiencydecreased. Therefore, it can be confirmed that an optimal relativepermeability μ_(r) exists. FIG. 20 is a graph showing a frequencycharacteristic of transmission efficiency when the relative permeabilityof the magnetic material 3 is changed in the power transfer system ofFIG. 11 in which the thickness of the magnetic material 3 is reduced. Inthe case of FIG. 20, the thickness of the magnetic material 3 was 1 mm,and the relative permeability μ_(r) identical to the value in the caseof FIG. 19 was used for the sake of comparison. By reducing thethickness of the magnetic material 3, the coupling coefficient k betweenthe transmitter coil 1 and the receiver coil 2 increases. Although theoptimal characteristic was obtained when the relative permeabilityμ_(r)=7 in the case of FIG. 19, it does not hold when the thickness ofthe magnetic material 3 is changed. FIG. 21 is a graph showing afrequency characteristic of transmission efficiency when the relativepermeability of the magnetic material 3 is changed in the power transfersystem of FIG. 11 in which the thickness of the magnetic material 3 isreduced. Also, in the case of FIG. 21, the thickness of the magneticmaterial 3 was 1 mm, whereas a relative permeability different fromthose of FIGS. 19 and 20 was used. According to FIG. 21, it can beunderstood that, when the thickness of the magnetic material 3 isreduced, a wide-band operation similar to that before the reduction inthickness can be achieved by using a magnetic material having a greatrelative permeability (e.g., μ_(r)=14). As described above, the powertransfer system of the present embodiment has such an particularadvantageous effect that the same system can cope with thicknessreduction by improving the relative permeability. Reducing the thicknessof the magnetic material 3 leads to reductions in cost and weight.

Next, a characteristic when a cavity is provided at the magneticmaterial 3 in the power transfer system of the present embodiment isdescribed with reference to FIGS. 22 to 24.

FIG. 22 is a top view showing a schematic configuration of a powertransfer system according to the second implemental example of thepresent disclosure.

The power transfer system of FIG. 22 has a configuration similar to thatof the power transfer system shown in FIGS. 11 to 14 except that acavity is provided at the magnetic material 3. The dimensions of thecavity are 14×14 mm. FIG. 23 is a graph showing a frequencycharacteristic of transmission efficiency when the relative permeabilityof the magnetic material 3 is changed in the power transfer system ofFIG. 22 in which the cavity is removed. FIG. 24 is a graph showing afrequency characteristic of transmission efficiency when the relativepermeability of the magnetic material 3 is changed in the power transfersystem of FIG. 22. By comparing the graphs of FIG. 23 and FIG. 24 witheach other, it can be understood that substantially similarcharacteristics can be obtained regardless of the existence of thecavity. In the power transfer system of the present embodiment, themagnetic material 3 needs only to be provided adjacent to thetransmitter coil 1 and the receiver coil 2 so as to cover at least onepart of the region in which at least the windings of the transmittercoil 1 and the receiver coil 2 exist. Providing the cavity at themagnetic material 3 leads to reductions in cost and weight.

Next, a further implemental example of the power transfer system of thepresent embodiment is described with reference to FIGS. 25 to 27.

FIG. 25 is a sectional view showing a schematic configuration of a powertransfer system according to the third implemental example of thepresent disclosure. FIG. 26 is a plan view showing a transmitter coil 1and a receiver coil 2 of FIG. 25. A magnetic material 11 and a metalshield 12 are provided for shielding below the transmitter coil 1, and amagnetic material 13 and a metal shield 14 are provided for shieldingalso above the receiver coil 2. The magnetic materials 11 and 13 and themetal shields 12 and 14 have a thickness of 0.1 mm. The shield has theadvantageous effects of reducing leakage electromagnetic fields andreducing influences on the peripheral units. The magnetic material 3 hasa relative permeability of 10, and the magnetic materials 11 and 13 havea relative permeability of 1000. As shown in FIG. 26, the transmittercoil 1 and the receiver coil 2 are circular coils that have an outerdiameter of 29 mm, an inner diameter of 12.5 mm, and a number of turnsof 17. The windings of the transmitter coil 1 and the receiver coil 2have a width of 0.48 mm and a thickness of 0.3 mm, and each of thetransmitter coil 1 and the receiver coil 2 has an inductance of 11.7 μHand a series resistance of 0.4Ω.

FIG. 27 is a graph showing a frequency characteristic of thetransmission efficiency of the power transfer system of FIG. 25. Thegraph of FIG. 27 shows results obtained by actual measurements.Simulations were carried out for the following cases: a case (solidline) of the distance d=2.6 mm between the transmitter coil 1 and thereceiver coil 2 with the magnetic material; a comparative case(alternate long and short dash line) of the distance d=2.6 mm with nomagnetic material; and a case (dotted line) of the distance d=7.5 mmwith no magnetic material. It is assumed that the thickness of themagnetic material 3 is equal to the distance d. In the case of “d=2.6 mmwith no magnetic material”, the transmitter coil 1 and the receiver coil2 are adjacent to be each other so as to be electromagnetically stronglycoupled to each other, and therefore, any wide band operation cannot beachieved although the transmission efficiency is maximized at afrequency of 150 kHz. In the case of “d=7.5 mm with no magneticmaterial”, the mutual inductance decreases due to the fact that thetransmitter coil 1 and the receiver coil 2 are separated to be apartfrom each other, and therefore, the coupling coefficient can bedecreased, consequently allowing the wide band operation to be achieved.However, in the case, the frequency at which the transmission efficiencybecomes maximized increases to 250 kHz. That is, the power transfersystem is substantially increased in size. On the other hand, in thecase of “d=2.6 mm with the magnetic material”, namely, the frequencycharacteristic of the transmission efficiency of the power transfersystem of the implemental example becomes maximized at 150 kHz, and itcan be understood that the bandwidth of transmission efficiency (e.g.,bandwidth in which the transmission efficiency becomes equal to orlarger than 60%) also has a wide band achieved by comparison with thecase of “d=2.6 mm with no magnetic material”. Moreover, by comparisonwith the case of “d=7.5 mm with no magnetic material”, the frequency atwhich the transmission efficiency becomes maximized is lowered. From theabove results, the power transfer system of the present embodiment hassuch particular advantageous effects that an increase in the bandwidthand a reduction in size can be concurrently achieved.

Several applications of the present disclosure are described below.

FIG. 28 is a block diagram showing a schematic configuration of thepower transfer system according to the first embodiment of the presentdisclosure. A power transfer system including the noncontact connectorsystem as described above can be configured. It is assumed that thepower transfer system is configured to include a power transferapparatus on the power transmitter side on which the noncontactconnector apparatus on the transmitter side is provided, and a powertransfer apparatus on the power receiver side on which the noncontactconnector apparatus on the receiver side is provided. Referring to FIG.28, in the power transfer apparatus on the power transmitter side, thetransmitter coil 1 (FIG. 1) is connected to a power transmitter circuit102, and the power transmitter circuit 102 is connected to a powersupply 101. In the power transfer apparatus on the power receiver side,the receiver coil 2 (FIG. 1) is connected to a power receiver circuit103, and the power receiver circuit 103 is connected to a load 104(e.g., a battery or the like). When power is supplied to the transmittercoil 1, a current flows in the transmitter coil 1, and an inducedelectromotive force is generated in the receiver coil 2 byelectromagnetic fields in the peripheries of the transmitter coil 1formed by the current, then an induced current flows in the receivercoil 2. By taking out this induced current by the load 104, the electricpower can be transferred between the transmitter coil 1 and the receivercoil 2.

FIG. 29 is a sectional view showing a configuration of the powertransfer apparatus on the power transmitter side and the power transferapparatus on the receiver side in the power transfer system of FIG. 25.In a case where the power transfer system of the present embodiment(e.g., wireless charging or the like) is implemented, it is beneficialto provide the transmitter coil 1 and the magnetic material 3 on theinside of the casing 4 of the power transfer apparatus (charger) on thepower transmitter side, and provide only the receiver coil 2 on theinside of the casing 5 of the power transfer apparatus (which is adevice to be charged) on the power receiver side. The receiver coil 2 isprovided so that the winding is wound around a predetermined region ofthe magnetic material 3 on the plane (second plane) opposed to the plane(first plane) on the side where the transmitter coil 1 is provided whenthe power transfer apparatus on the power receiver side is put to beadjacent to the power transfer apparatus on the power transmitter side.When the power transfer is not performed, the receiver coil 2 is locatedto be apart from the transmitter coil 1 and the magnetic body 3. Whenpower transfer is performed by putting the power transfer apparatus onthe power receiver side to be adjacent to the power transfer apparatuson the power transmitter side, the receiver coil 2 is put to be adjacentto the magnetic body 3 so as to cover at least one part of the region inwhich the winding of the receiver coil 2 exists, and the self-inductanceof the receiver coil 2 is increased by putting the receiver coil 2 to beadjacent to the magnetic body 3. Subsequently, an operation is performedin a manner similar to that of the case described with reference to FIG.1 and so on.

FIG. 30 is a sectional view showing a configuration of a modifiedembodiment of the power transfer apparatus on the power transmitter sideand the power transfer apparatus on the power receiver side in the powertransfer system of FIG. 25. Magnetic bodies may be provided for both ofthe power transfer apparatus on the power transmitter side and the powertransfer apparatus on the power receiver side. In the power transfersystem of FIG. 30, a transmitter coil 1 and a magnetic body 3 a areprovided in the casing 4 of the power transfer apparatus on the powertransmitter side, and only a magnetic body 3 b and a receiver coil 2 areprovided in the casing 5 of the power transfer apparatus on the powerreceiver side. When the power transfer is not performed, the receivercoil 2 is located to be apart from the transmitter coil 1. When thepower transfer is performed by putting the power transfer apparatus onthe power receiver side to be adjacent to the power transfer apparatuson the power transmitter side, the receiver coil 2 iselectromagnetically coupled to the transmitter coil 1. By increasing theself-inductances of the transmitter coil 1 and the receiver coil 2 withthe magnetic bodies 3 a and 3 b, the coupling coefficient between thetransmitter coil 1 and the receiver coil 2 can be set to be decreased sothat the frequency characteristic of transmission efficiency from thetransmitter coil 1 to the receiver coil 2 changes from a double-peakednarrow-band characteristic to a single-peaked wide-band characteristic.Subsequently, the same system operates in a manner similar to that ofthe case described with reference to FIG. 1 and so on.

In FIGS. 29 and 30, the casings 4 and 5 are made of, for example, adielectric or an insulator such as ABS resin or rubber or both of them.It is also possible to configure at least one of the casings 4 and 5made of a magnetic body. For example, by mixing magnetic body powderswith the casing (dielectric), the relative permeability of the casingcan be increased. Further, it is also possible to integrate the magneticbody 3 with the casing 4 or 5 made of a magnetic body. By integratingthe magnetic body 3 with the casing 4 or 5, the power transfer systemhas such an effect that the same system can be reduced in thickness, andbecause of a reduction in the number of members, cost reduction andweight reduction can be expected.

According to the power transfer system of the present embodiment, powercan be transferred with a stabilized transmission efficiency with a verysimple configuration even if a positional misalignment occurs betweenthe transmitter coil 1 and the receiver coil 2.

Second Embodiment

FIG. 31 is a block diagram showing a schematic configuration of a signaltransmission system according to the second embodiment of the presentdisclosure. It is acceptable to transmit a signal instead oftransmitting power by using the noncontact connector system describedabove. It is defined that the signal transmission system is configuredto include an information transmission apparatus on the transmitter sideincluding a noncontact connector apparatus on the transmitter side, andan information transmission apparatus on the receiver side including anoncontact connector apparatus on the receiver side. Referring to FIG.31, the transmitter coil 1 (FIG. 1) is connected to a transmittercircuit 112, and the transmitter circuit 112 is connected to a signalsource 111 in the information transmission apparatus on the transmitterside. In the information transmission apparatus on the receiver side,the receiver coil 2 (FIG. 1) is connected to a receiver circuit 113. Theinformation transmission apparatus on the transmitter side and theinformation transmission apparatus on the receiver side in the signaltransmission system can be configured in a manner similar to that of thepower transfer apparatus on the power transmitter side and the powertransfer apparatus on the power receiver side shown in FIG. 29 or FIG.30. According to the information transmission system of the presentembodiment, information can be transmitted with a stabilizedtransmission efficiency with a very simple configuration even if apositional misalignment occurs between the transmitter coil 1 and thereceiver coil 2.

Third Embodiment

FIG. 32 is a block diagram showing a schematic configuration of aninduction heating apparatus according to the third embodiment of thepresent disclosure. FIG. 33 is a sectional view showing a configurationof the induction heating apparatus and the pan 123 of FIG. 32. Aninduction heating apparatus can be configured by using the principle ofthe power transfer system described above.

Referring to FIG. 32, the transmitter coil 1 (FIG. 1) as an inductionheating coil is connected to a cooking circuit 122, and the cookingcircuit 122 is connected to a power supply 121 in the induction heatingapparatus. Further, a cooking container for induction heating such asthe pan 123 is provided in place of the receiver coil 2 of FIG. 1. Thepan 123 is provided adjacent to the transmitter coil 1 so as to beelectromagnetically coupled to the transmitter coil 1. When a currentflows in the transmitter coil 1 due to electromagnetic coupling betweenthe transmitter coil 1 and the pan 123, an induced electromotive forceis generated in the basal plane of the pan 123 due to electromagneticfields in the peripheries of the transmitter coil 1 formed by thecurrent, and an induced eddy current flows in the basal plane of the pan123. Since this eddy current can be equivalently regarded as a lossycoil, the self-inductance of the pan 123 and a mutual inductance betweenthe transmitter coil 1 and the pan 123 can be defined. The transmittercoil 1 is provided along a first plane so that a winding is wound arounda predetermined region on the horizontal first plane. The inductionheating apparatus is configured to include a magnetic body 3, that isprovided between the first plane and a second plane which is locatedabove to be opposed and to be adjacent to the first plane and in whichthe basal plane of the pan 123 is located. The magnetic body 3 isprovided to be adjacent so as to be electromagnetically coupled to thetransmitter coil 1 and the basal plane of the pan 123 throughout aregion in which at least the winding of the transmitter coil 1 and thebasal plane of the pan 123 exist between the first plane and the secondplane. The self-inductance of the transmitter coil 1 is increased byputting the magnetic body 3 to be adjacent to the transmitter coil 1,and the self-inductance of the pan 123 is increased by putting themagnetic body 3 to be adjacent to the basal plane of the pan 123.

The induction heating apparatus of the present embodiment ischaracterized in that the coupling coefficient between the transmittercoil 1 and the pan 123 is set to be decreased by increasing theself-inductance of each of the transmitter coil 1 and the pan 123 sothat the frequency characteristic of the transmission efficiency fromthe transmitter coil 1 to the pan 123 changes from a double-peakednarrow-band characteristic to a single-peaked wide-band characteristic.According to the induction heating apparatus of the present embodiment,the pan 123 can be heated with a stabilized transmission efficiency witha very simple configuration even if a positional misalignment occursbetween the transmitter coil 1 and the pan 123.

Modified Embodiments

Modified embodiments of the embodiments of the present disclosure aredescribed with reference to FIGS. 34 to 36. Although the winding of thetransmitter coil 1 is wound in a single layer along the first plane, andthe winding of the receiver coil 2 is wound in a single layer along thesecond plane in the embodiments and the implemental examples describedwith reference to FIG. 1 and so on, the windings may be wound in aplurality of layers.

FIG. 34 is a sectional view showing a modified embodiment of thetransmitter coil 1 and the receiver coil 2 of FIG. 1. FIG. 35 is aschematic diagram for explaining a winding method of the transmittercoil 1 of FIG. 34. In FIGS. 34 and 35, a case where the transmitter coil1 and the receiver coil 2 are each wound in two layers is shown. Thewindings 1 a and 1 b of the layers of the transmitter coil 1 are woundin directions opposite to each other, and the windings 1 a and 1 b areconnected in series to each other by connecting them at terminals Pb andPd. By connecting the windings 1 a and 1 b in series, the modifiedembodiment has such an effect that the inductance of the transmittercoil 1 can be increased. The same thing can be said for the receivercoil 2.

FIG. 36 is a schematic diagram for explaining a modified embodiment ofthe winding method of the transmitter coil 1 of FIG. 34. The windings 1a and 1 b of the layers of the transmitter coil 1 are wound in anidentical direction, and the windings 1 a and 1 b are connected inparallel to each other by connecting them at terminals Pa and Pc andfurther connecting them at terminals Pb and Pd. By connecting thewindings 1 a and 1 b in parallel, the modified embodiment has such aneffect that the resistance of the transmitter coil 2 can be reduced.

It is noted that the total length of each of the transmitter coil 1 andthe receiver coil 2 needs to be drastically shortened with respect tothe operating wavelength.

At least one of the transmitter coil 1 and the receiver coil 2 may bewound in a plurality of layers. Moreover, both or at least one of thetransmitter coil 1 and the receiver coil 2 may be wound in three or morelayers.

FIG. 37 is a sectional view showing a modified embodiment of thenoncontact connector apparatus on the transmitter side and the receiverside of FIG. 1. The noncontact connector apparatus may be formed on aprinted wiring board. In this case, the transmitter coil 1 and thereceiver coil 2 are formed as respective conductor patterns ondielectric substrates 7 and 8. A magnetic body 3 a is applied onto thetransmitter coil 1 and the dielectric substrate 7, and a magnetic body 3b is applied onto (lower surface of the dielectric substrate 8 in FIG.37) the receiver coil 2 and the dielectric substrate 8. By thusintegrally forming the transmitter coil 1 and the receiver coil 2 on theprinted wiring board with the magnetic bodies 3 a and 3 b, ahigh-strength low-cost noncontact connector apparatus can be provided.Moreover, it is acceptable to integrally form the transmitter coil 1 orthe receiver coil 2 on the printed wiring board with the magnetic bodyin at least one of the noncontact connector apparatuses on thetransmitter side and the receiver side.

Moreover, although the capacitors for impedance matching, with which thetransmitter coil 1 and the receiver coil 2 are loaded, are connected inparallel with the transmitter coil 1 and the receiver coil 2 in FIG. 14,they may be connected in series as shown in FIG. 4. Moreover, anotherimpedance matching circuit may also be used.

The principle of operation of the present disclosure is complementedhere. Considering a case where radio waves are radiated from atransmitting antenna to a receiving antenna as a comparison to thepresent disclosure, the bandwidth does not change even if a relativerelation between the antennas changes since the transmitting antenna andthe receiving antenna are separated to be apart from each other and areput in an electromagnetically uncoupled state. However, since thetransmitter coil and the receiver coil are adjacent to each other so asto be electromagnetically coupled to each other in the noncontactconnector system, the bandwidth fluctuates in accordance with thecoupling state. Therefore, if a narrow-band design is unfortunatelymade, the frequency at which the transmission efficiency becomesmaximized shifts even with a slight change in the distance between thetransmitter coil and the receiver coil, and the transmission efficiencydisadvantageously decreases as a result. In the noncontact connectorsystem described in the embodiments of the present disclosure, wide bandoperation is achieved by providing the magnetic body 3 between thetransmitter coil 1 and the receiver coil 2, and fluctuations in thetransmission efficiency can be suppressed even if the frequency at whichthe transmission efficiency becomes maximized changes due to somepositional misalignment as a result (See FIG. 17). By thus achieving thewide band operation, the transmission efficiency can be maintained atthe desired frequency even when a positional misalignment occurs betweenthe transmitter coil 1 and the receiver coil 2.

Prior arts include one in which a magnetic body is provided between thetransmitter coil and the receiver coil, and, for example, the inventiondisclosed in the Patent Document 1 has been known. However, since theinvention of the Patent Document 1 uses the magnetic body in order toincrease the coupling coefficient between the transmitter coil and thereceiver coil in a manner similar to that of FIG. 8 of the presentapplication, it is quite different from the purpose of using themagnetic body in the present disclosure, i.e., using the same magneticbody for decreasing the coupling coefficient by increasing theself-inductance of each of the transmitter coil 1 and the receiver coil2. The magnetic body used in the invention of the Patent Document 1 hasa high relative permeability in order to increase the couplingcoefficient. On the other hand, the magnetic body used in the presentdisclosure is able to have a comparatively small relative permeability.

Fourth Embodiment

FIG. 38 is a perspective view showing a schematic configuration of apower transfer system according to the fourth embodiment of the presentdisclosure. In FIG. 38, a power transmitter circuit according to theembodiment includes a magnetic body 3 having a transmitter coil 1 maycharge or feed electric power to a power receiver circuit according toan embodiment in, for example, a smart phone 201 or another portabletelephone including a receiver coil 2.

Fifth Embodiment

FIG. 39 is a perspective view showing a schematic configuration of apower transfer system according to the fifth embodiment of the presentdisclosure. Referring to FIG. 39, a power transmitter circuit accordingto the embodiment that is configured to include a magnetic body 3including a transmitter coil 1 may charge or feed electric power to apower receiver circuit according to an embodiment in, for example,tablet terminal device 202 or another information terminal apparatusincluding a receiver coil 2.

FIG. 40 is a vertical sectional view showing a schematic configurationof a power transfer system according to the fourth implemental exampleof the present disclosure. FIG. 41 is a graph showing a characteristicof the coupling coefficient k with respect to a magnetic permeabilityratio of μ2/μ1 when a normalized inter-coil distance d/D is used as aparameter in the power transfer system of FIG. 40. A concrete designexample is described below with reference to FIGS. 40 and 41.

FIG. 40 shows only the outermost peripheries of the transmitter coil 1and the receiver coil 2 each having the same number of turns, and theinternal diameter of the outer periphery is assumed to be D. Moreover, amagnetic body 3 having a thickness “d” and a magnetic permeability “μ2”is interposed between the casings 4 and 5 each having a magneticpermeability “μ1”.

Generally speaking, in the power transfer system configured as above,efficiency η=|S21|² can be determined by a product of the couplingcoefficient k and the Q values of the coils 1 and 2. In the powertransfer system, high efficiency is an indispensable factor, and it isbeneficial that kQ>20 in concrete to achieve an efficiency equal to orlarger than 90%. For example, when coils 1 and 2 with Q=100 or less areused, it is beneficial that the coupling coefficient should be equal toor larger than 0.2 in order to achieve kQ>20. However, since thedouble-peaked narrow-band characteristic is exhibited as described abovewhen the coupling coefficient is excessively strong, it is beneficialthat the coupling coefficient should be equal to or smaller than 0.6 inorder to achieve a wide band.

In view of the above, design is made to determine the magneticpermeability of the magnetic body 3 between the coils 1 and 2 so that0.2≦k≦0.6 is achieved with regard to the coupling coefficient k. Upondetermining the magnetic permeability μ1 of the casings 4 and 5, it isbeneficial to select different values depending on the magneticpermeability μ2 of the magnetic body 3 that is the shield member placedon the rear side of the coils 1 and 2. In this case, the magnetic body 3of the shield member is placed for the purpose of reducing leakageelectromagnetic fields to the adjacent electronic device and the like. Aconcrete design example is described below.

Those who provide the present disclosure calculated by simulations thediameter D mm, the number of turns 1, and the coupling coefficient kbetween the coils 1 and 2 of the inter-coil distance d as shown in FIG.40. It is assumed that the magnetic permeability of the magnetic body 3on the rear side of the coils 1 and 2 is μ1, and the magneticpermeability of the magnetic body between the coils is μ2.

According to the calculation results of FIG. 41, it can be understoodthat the coupling coefficient k decreases as the magnetic permeabilityratio μ2/μ1 increases. As described above, in order to achieve 0.2≦k≦0.6with regard to the coupling coefficient k, it is beneficial to makeμ2/μ1 have a value larger than one in the case of adjacency that thenormalized inter-coil distance d/D is equal to or smaller than 0.2.However, if it is made excessively large, it does not satisfy the targetrange of the coupling coefficient depending on the degree of adjacency.Therefore, it is useful that the range of μ2/μ1 is equal to or largerone and is equal to or smaller than 100. In FIG. 41, the hatched region300 indicates the useful region of the present implemental example.

Although the “noncontact connector apparatus” or the like is mentionedin each of the above embodiments and modified embodiments, the sameapparatus may be called as a “contactless connector apparatus” or thelike since it is a connector apparatus of power transfer without contactpoints.

Summary of the Embodiments

According to a first aspect of the present disclosure, there is providedan information transmission apparatus including a transmitter circuitconfigured to transmit information to a receiver circuit connected to areceiver coil; and a first noncontact connector apparatus connected tothe transmitter circuit. The first noncontact connector apparatuscomprises a transmitter coil, that is provided to be adjacent so as tobe electromagnetically coupled to the receiver coil, and a winding ofthe transmitter coil is wound on a first plane. The informationtransmission apparatus includes a first magnetic body provided betweenthe first plane and a second plane which is opposed to be adjacent tothe first plane and on which the receiver coil is provided, and thefirst magnetic body is provided to be adjacent so as to beelectromagnetically coupled to the transmitter coil and to cover atleast one part of a region in which at least the winding of thetransmitter coil exists.

According to a second aspect of the present disclosure, in theinformation transmission apparatus according to the first aspect of thepresent disclosure, a self-inductance of the transmitter coil isincreased by putting the first magnetic body to be adjacent to thetransmitter coil.

According to a third aspect of the present disclosure, there is providedan information transmission apparatus including: a receiver circuitconfigured to receive information from a transmitter circuit connectedto a transmitter coil; and a second noncontact connector apparatusconnected to the receiver circuit. The second noncontact connectorapparatus includes a receiver coil, that is provided to be adjacent soas to be electromagnetically coupled to the transmitter coil, and awinding of the receiver coil is wound on a second plane that is opposedto be adjacent to the first plane on which the transmitter coil isprovided. The information transmission apparatus includes a secondmagnetic body provided between the first plane and the second plane, andthe second magnetic body is provided to be adjacent so as to beelectromagnetically coupled to the receiver coil and to cover at leastone part of a region in which at least the winding of the receiver coilexists.

According to a fourth aspect of the present disclosure, in theinformation transmission apparatus according to the third aspect of thepresent disclosure, a self-inductance of the receiver coil is increasedby putting the second magnetic body to be adjacent to the receiver coil.

According to a fifth aspect of the present disclosure, there is providedan information transmission system including: the informationtransmission apparatus according to the first or second aspect of thepresent disclosure serving as a first information transmission apparatusincluding the transmitter circuit; and a second information transmissionapparatus including the receiver circuit, and a second noncontactconnector apparatus connected to the receiver circuit. The secondnoncontact connector apparatus comprises a receiver coil including awinding wound on the second plane. The first magnetic body is furtherput to be adjacent to the receiver coil to be electromagneticallycoupled to the receiver coil and to cover at least one part of a regionin which at least the winding of the receiver coil exists between thefirst plane and the second plane, thereby increasing the self-inductanceof the receiver coil by putting the first magnetic body to be adjacentto the receiver coil. A coupling coefficient between the transmittercoil and the receiver coil is set to be decreased by increasing theself-inductance of each of the transmitter coil and the receiver coil sothat a frequency characteristic of transmission efficiency from thetransmitter coil to the receiver coil changes from a double-peakednarrow-band characteristic to a single-peaked wide-band characteristic.

According to a sixth aspect of the present disclosure, there is providedan information transmission system including: the informationtransmission apparatus according the first or second aspect of thepresent disclosure serving as a first information transmission apparatusincluding the transmitter circuit; and the information transmissionapparatus according to the third or fourth aspect of the presentdisclosure serving as a second information transmission apparatusincluding the receiver circuit. A coupling coefficient between thetransmitter coil and the receiver coil is set to be decreased byincreasing the self-inductance of each of the transmitter coil and thereceiver coil so that a frequency characteristic of transmissionefficiency from the transmitter coil to the receiver coil changes from adouble-peaked narrow-band characteristic to a single-peaked wide-bandcharacteristic.

According to a seventh aspect of the present disclosure, in theinformation transmission system according to the sixth aspect of thepresent disclosure, the magnetic permeability of the first magnetic bodyis set so that the coupling coefficient is set to be equal to or largerthan 0.2 and to be equal to or smaller than 0.6.

According to an eighth aspect of the present disclosure, in the aninformation transmission system according to any one of the fifth toseventh aspects of the present disclosure, a winding of the transmittercoil is wound in a single layer along the first plane, and the windingof the receiver coil is wound in a single layer along the second plane.

According to a ninth aspect of the present disclosure, in the aninformation transmission system according to any one of the fifth toseventh aspects of the present disclosure, the winding of at least oneof the transmitter coil and the receiver coil is wound in a plurality oflayers along the first or second plane, and the windings of the layersbelonging to the windings of the plurality of layers are connected inseries to each other.

According to a tenth aspect of the present disclosure, in the aninformation transmission system according to any one of the fifth toseventh aspects of the present disclosure, the winding of at least oneof the transmitter coil and the receiver coil is wound in a plurality oflayers along the first or second plane, and the windings of the layersbelonging to the windings of the plurality of layers are connected inparallel to each other.

According to an eleventh aspect of the present disclosure, in the aninformation transmission system according to the fifth aspect of thepresent disclosure, the winding of the transmitter coil is formed as aconductor pattern on a first dielectric substrate along the first plane,and the first magnetic body is formed integrally with the transmittercoil and the first dielectric substrate.

According to a twelfth aspect of the present disclosure, in the aninformation transmission system according to the sixth or seventh aspectof the present disclosure, the winding of the transmitter coil is formedas a conductor pattern on the first dielectric substrate along the firstplane, and the first magnetic body is formed integrally with thetransmitter coil and the first dielectric substrate. The winding of thereceiver coil is formed as a conductor pattern on a second dielectricsubstrate along the second plane, and the second magnetic body is formedintegrally with the receiver coil and the second dielectric substrate.

INDUSTRIAL APPLICABILITY

According to the noncontact connector apparatus, the noncontactconnector system, the power transfer apparatus and the power transfersystem of the present disclosure, power can be transmitted with astabilized transmission efficiency with a very simple configuration evenif a positional misalignment occurs between the transmitter coil and thereceiver coil.

According to the information transmission apparatus and the informationtransmission system of the present disclosure, information can betransmitted with a stabilized transmission efficiency with a very simpleconfiguration even if a positional misalignment occurs between thetransmitter coil and the receiver coil.

According to the induction heating apparatus of the present disclosure,the cooking container can be heated with a stabilized transmissionefficiency with a very simple configuration even if a positionalmisalignment occurs between the induction heating coil and the cookingcontainer.

REFERENCE NUMERALS

-   1, 1 a, 1 b: Transmitter coil-   2, 2 a, 2 b: Receiver coil-   3, 3 a, 3 b, 6, 11, 13: Magnetic body-   4, 5: Casing-   7, 8: Dielectric substrate-   12, 14: Metal shield-   101: Power supply-   102: Power transmitter circuit-   103: Power receiver circuit-   104: Load-   111: Signal source-   112: Transmitter circuit-   113: Receiver circuit-   121: Power supply-   122: Cooking circuit-   123: Pan-   201: Smart phone-   202: Tablet terminal device-   C1 to C4: Capacitance-   L1, L2: Self-inductance-   M: Mutual inductance-   P1 a, P1 b, P2 a, P2 b, Pa, Pb, Pc, Pd: Terminal-   R1, R2: Resistor-   Q, Q1: Signal source-   z01, z02, Z1: Load impedance

1-12. (canceled)
 13. An information transmission apparatus comprising: atransmitter circuit configured to transmit information to a receivercircuit connected to a receiver coil; and a first noncontact connectorapparatus connected to the transmitter circuit, wherein the firstnoncontact connector apparatus comprises a transmitter coil, that isprovided to be adjacent so as to be electromagnetically coupled to thereceiver coil, and a winding of the transmitter coil is wound on a firstplane, and wherein the information transmission apparatus comprises: afirst magnetic body provided between the first plane and a second planewhich is opposed to be adjacent to the first plane and on which thereceiver coil is provided, the first magnetic body being provided to beadjacent so as to be electromagnetically coupled to the transmitter coiland to cover at least one part of a region in which at least the windingof the transmitter coil exists.
 14. The information transmissionapparatus as claimed in claim 13, wherein a self-inductance of thetransmitter coil is increased by putting the first magnetic body to beadjacent to the transmitter coil.
 15. An information transmissionapparatus comprising: a receiver circuit configured to receiveinformation from a transmitter circuit connected to a transmitter coil;and a second noncontact connector apparatus connected to the receivercircuit, wherein the second noncontact connector apparatus comprises areceiver coil, that is provided to be adjacent so as to beelectromagnetically coupled to the transmitter coil, and a winding ofthe receiver coil is wound on a second plane that is opposed to beadjacent to the first plane on which the transmitter coil is provided,and wherein the information transmission apparatus comprises: a secondmagnetic body provided between the first plane and the second plane, thesecond magnetic body being provided to be adjacent so as to beelectromagnetically coupled to the receiver coil and to cover at leastone part of a region in which at least the winding of the receiver coilexists.
 16. The information transmission apparatus as claimed in claim15, wherein a self-inductance of the receiver coil is increased byputting the second magnetic body to be adjacent to the receiver coil.17. An information transmission system comprising: a first informationtransmission apparatus including a transmitter circuit configured totransmit information to a receiver circuit connected to a receiver coil,and a first noncontact connector apparatus connected to the transmittercircuit; and a second information transmission apparatus including areceiver circuit configured to receive information from the transmittercircuit, and a second noncontact connector apparatus connected to thereceiver circuit, wherein the first noncontact connector apparatuscomprises a transmitter coil, that is provided to be adjacent so as tobe electromagnetically coupled to the receiver coil, and a winding ofthe transmitter coil is wound on a first plane, and wherein theinformation transmission apparatus comprises: a first magnetic bodyprovided between the first plane and a second plane which is opposed tobe adjacent to the first plane and on which the receiver coil isprovided, the first magnetic body being provided to be adjacent so as tobe electromagnetically coupled to the transmitter coil and to cover atleast one part of a region in which at least the winding of thetransmitter coil exists, wherein the second noncontact connectorapparatus comprises the receiver coil including a winding wound on thesecond plane, wherein the first magnetic body is further put to beadjacent to the receiver coil to be electromagnetically coupled to thereceiver coil and to cover at least one part of a region in which atleast the winding of the receiver coil exists between the first planeand the second plane, thereby increasing the self-inductance of thereceiver coil by putting the first magnetic body to be adjacent to thereceiver coil, and wherein a coupling coefficient between thetransmitter coil and the receiver coil is set to be decreased byincreasing the self-inductance of each of the transmitter coil and thereceiver coil so that a frequency characteristic of transmissionefficiency from the transmitter coil to the receiver coil changes from adouble-peaked narrow-band characteristic to a single-peaked wide-bandcharacteristic.
 18. An information transmission system comprising: afirst information transmission apparatus including a transmitter circuitconfigured to transmit information to a receiver circuit connected to areceiver coil, and a first noncontact connector apparatus connected tothe transmitter circuit; and a second information transmission apparatusincluding a receiver circuit configured to receive information from thetransmitter circuit, and a second noncontact connector apparatusconnected to the receiver circuit, wherein the first noncontactconnector apparatus comprises a transmitter coil, that is provided to beadjacent so as to be electromagnetically coupled to the receiver coil,and a winding of the transmitter coil is wound on a first plane, andwherein the first information transmission apparatus comprises: a firstmagnetic body provided between the first plane and a second plane whichis opposed to be adjacent to the first plane and on which the receivercoil is provided, the first magnetic body being provided to be adjacentso as to be electromagnetically coupled to the transmitter coil and tocover at least one part of a region in which at least the winding of thetransmitter coil exists, wherein the second noncontact connectorapparatus comprises the receiver coil including a winding wound on thesecond plane, wherein the second information transmission apparatuscomprises a second magnetic body provided between the first plane andthe second plane, the second magnetic body being provided to be adjacentso as to be electromagnetically coupled to the receiver coil and tocover at least one part of a region in which at least the winding of thereceiver coil exists, and wherein a coupling coefficient between thetransmitter coil and the receiver coil is set to be decreased byincreasing the self-inductance of each of the transmitter coil and thereceiver coil so that a frequency characteristic of transmissionefficiency from the transmitter coil to the receiver coil changes from adouble-peaked narrow-band characteristic to a single-peaked wide-bandcharacteristic.
 19. The information transmission system as claimed inclaim 18, wherein the magnetic permeability of the first magnetic bodyis set so that the coupling coefficient is set to be equal to or largerthan 0.2 and to be equal to or smaller than 0.6.
 20. The informationtransmission system as claimed in claim 17, wherein the winding of thetransmitter coil is wound in a single layer along the first plane, andwherein the winding of the receiver coil is wound in a single layeralong the second plane.
 21. The information transmission system asclaimed in claim 17, wherein the winding of at least one of thetransmitter coil and the receiver coil is wound in a plurality of layersalong the first or second plane, and wherein the windings of the layersbelonging to the windings of the plurality of layers are connected inseries to each other.
 22. The information transmission system as claimedin claim 17, wherein the winding of at least one of the transmitter coiland the receiver coil is wound in a plurality of layers along the firstor second plane, and wherein the windings of the layers belonging to thewindings of the plurality of layers are connected in parallel to eachother.
 23. The information transmission system as claimed in claim 17,wherein the winding of the transmitter coil is formed as a conductorpattern on a first dielectric substrate along the first plane, andwherein the first magnetic body is formed integrally with thetransmitter coil and the first dielectric substrate.
 24. The informationtransmission system as claimed in claim 18, wherein the winding of thetransmitter coil is formed as a conductor pattern on the firstdielectric substrate along the first plane, wherein the first magneticbody is formed integrally with the transmitter coil and the firstdielectric substrate, wherein the winding of the receiver coil is formedas a conductor pattern on a second dielectric substrate along the secondplane, and wherein the second magnetic body is formed integrally withthe receiver coil and the second dielectric substrate.